The SEMA show is currently underway, and it's a predictably eclectic gathering of outlandish custom cars all in one place. Audi's contribution to the show is subtle in comparison to some of the eye-catching cars at the show, but no less special. Making its North American debut is the Audi TT Clubsport Turbo, a sleek concept built as tribute to the 90 IMSA GTO from the 1980s which is considered by many as one of the greatest race cars ever built. Both its appearance and performance mimic the GTO racer.

Powering the TT Clubsport Turbo is a 600-hp five-cylinder TFSI engine with an electronically assisted turbocharger, just like the original race car. With this setup, the Audi TT Clubsport Turbo Concept sprints from 0-62 mph in just 3.6 seconds on its way to a top speed of 192 mph. Yes, that's entering supercar territory. In terms of design, Audi says the concept takes the "TT silhouette to the extreme," featuring angular fenders like the original 1980s race car which makes it 5.5 inches wider than the production TT road car to "accentuate the quattro drive". It also sports a manually-adjustable carbon fiber rear wing to provide extra downforce.

For now, the Audi TT Clubsport Turbo is just a one-off concept, so it isn't clear if the German automaker plans to put it into production. Audi is also showcasing a range of Sport Performance parts that will soon be available for the new Audi TT RS enhancing the suspension, exhaust system, exterior and interior, some of which can be seen on the Clubsport Concept. The TT RS being displayed at the show with Audi Sport Performance Parts is fitted with a two-way adjustable coilover suspension, additional chassis bracing, and brake system enhancements. It rides on lightweight 20-inch wheels with high-performance sport tires.

A range of aerodynamic enhancements produce additional downforce at speed, while additional air ducts provide extra brake cooling. Rounding off the exterior enhancements is an Audi Sport Performance titanium exhaust created in collaboration with Akrapovic. Inside, the TT RS includes an Audi Sport Performance steering wheel with carbon shift paddles. Pricing and availability has yet to be confirmed. Also on show is Audi's R8 LMS race car, which shares over 50 percent of its parts with the Audi R8 road car including its naturally aspirated 5.2-liter V10, which sends 495-hp exclusively to the rear wheels.